CN110691759B - Method and apparatus for shaping glass sheets - Google Patents

Abstract

A method of shaping a glass sheet (50) is described, the method comprising: providing a forming support (15) for supporting the glass sheet; providing a bending apparatus comprising at least a first (17) mold Parts and a second (19) mold part, each mold part is movable relative to the forming support; the glass sheet is heated; the glass sheet is positioned on the forming support; at least moving one towards the other to press the glass sheet in a first region of the glass sheet between the forming support and the first mold part (17); moving the second mold part (19) relative to the first mold part to press the glass sheet in the second region of the glass sheet, and move the first mold part relative to the forming support to between the first mold part and the second mold part, in the first region of the glass sheet The glass plates are further pressed. Apparatuses useful for carrying out the method are also described.

Description

Method and apparatus for forming glass sheets

The invention relates to a method of shaping a glass sheet and an apparatus for shaping a glass sheet.

Bending or shaping flat glass sheets between a pair of shaping members having complementary shaping surfaces is well known in the art. Typically, the heat softened glass sheet is supported on a ring mold and bent between the ring mold and the upper integral full surface mold.

US2015/0000340A1 relates to a device for forming glass, which includes a lower mold, a fixed mold and an upper mold. Similar technologies in the field of display glass include KR10-2015-0048450A and US2015/0274570A1.

JPS638229A relates to forming flat glass into a hollow ultra-thin glass product with a smooth surface and stable dimensions by fixing formable heated glass to a guide ring, pressing a plunger against the glass and forcing the glass into an opening portion.

US 5,401,286 relates to a flexible ring mold for shaping heat-softened glass sheets wherein an inner ring is provided with a plurality of posts which assist in supporting the supported glass sheet during initial lifting and shaping Ring the mold and hold the mold in a generally planar configuration.

In WO 2005/033026 A1 a press bending station is described comprising a ring die and a full surface die. Holes selectively connected to a source of negative pressure are placed in sections of the full-surface mould, the location of which is determined by the configuration of the ring mold when it comes into contact with the heated glass sheet during press bending. The heated glass sheet is sucked by negative pressure through the holes towards the full-surface mold, thereby acquiring its shape. Full surface molds can be covered with at least one fine mesh fabric, ie woven stainless steel.

In order to manufacture certain complex curved glass shapes that may have special uses such as glazing in vehicle windows, it is sometimes not possible to bend the glass into the desired shape using integral press bending components. It has been found that, for certain shapes, the use of integral press bending components partially corrugates the edge of the glass during the bending operation, resulting in wrinkles in the edge of the glass that produce at least optical distortion.

In the prior art, this problem can be overcome by supporting the glass sheet on a lower ring mold and using an upper press bending part made of more than one moving part, as described in US 5,122,177. In US Pat. No. 5,122,177 it is described how to support the edges of a glass sheet to be bent on a forming frame, first clamping the glass sheet at its peripheral edge and then pressing the central region of the glass sheet to the desired curvature.

A similar two-part mold is described in US2015/0007612A1.

However, it has been found that when using such two-part press bending parts as described in the prior art, the press bending operation can induce very high stresses in the glass sheet during the bending operation for certain desired bent glass shapes , so that the glass sheet may break when it is formed.

The present invention aims at overcoming the above-mentioned problems at least in part.

Thus, viewed from a first aspect, the present invention provides a method of forming a glass sheet, the method comprising the steps of: (i) providing a forming support for supporting the glass sheet; (ii) providing a press A bending device comprising at least two (first and second) mold parts, each of the first mold part and the second mold part being movable relative to the forming support; (iii) for the glass sheet applying heat; (iv) positioning the glass sheet on the forming support; (v) moving at least one of the forming support and press bending device towards the other to be between the forming support and the first mold part, compressing the glass sheet in the first region of the glass sheet; (vi) moving the second mold part relative to the first mold part to compress the glass sheet in the second region of the glass sheet, and (vii) causing The first mold part is moved relative to the forming support to further compress the glass sheet in a first region of the glass sheet between the first mold part and the forming support.

For the avoidance of doubt, the first mold part is movable relative to the forming support, the second mold part is movable relative to the forming support and the first mold part is movable relative to the second mold part.

During step (v), the glass sheet is pressed between the forming support and the first mold part with sufficient force to allow the second mold part to bend the glass sheet during step (vi), but during step In (v), the first mold part is not in a final position relative to the forming support to provide the glass sheet with the final desired curvature in the first region of the glass sheet.

During step (vii), the glass sheet is pressed between the forming support and the first mold part to provide the glass sheet with the final desired curvature in the first region of the glass sheet.

It has been found that by only partially clamping the first region of the glass sheet during step (v), step (vii) is added to further condition the glass sheet in the first region between the first mold part and the forming support. Pressing, which reduces the amount of glass breakage during the forming process.

Preferably, prior to step (v), the press bending device is configured such that the press bending device is not in contact with the glass sheet in the second region of the glass sheet before or during step (v).

Preferably, the press bending device is in contact with the glass sheet in the second region of the glass sheet before step (v) or during step (v). In particular, it is preferred that the second mold part is in contact with the glass sheet in the second region of the glass sheet before step (v) or during step (v).

Preferably, also during step (vii) the second mold part is moved relative to the forming support for further bending of the glass sheet in the second region of the glass sheet. When the second mold part is moved relative to the forming support during step (vii), the second mold part may also be moved relative to the first mold part.

Preferably, when the second mold part is moved relative to the forming support during step (vii), the movements of the first mold part and the second mold part relative to the forming support are synchronized.

Preferably, the first region of the glass sheet is a peripheral region of the glass sheet. Preferably, the peripheral region extends around the entire periphery of the glass pane.

Preferably, the second region of the glass pane is a central region of the glass pane.

Preferably, the first region of the glass pane is a peripheral region of the glass pane, in particular a peripheral region extending around the entire periphery of the glass pane, and the second region of the glass pane is a central region of the glass pane, the central region of the glass pane being at the edge of the glass pane. The inside of the perimeter area of the board.

Preferably, the forming support comprises at least one rail for supporting the glass sheet around its peripheral region. Preferably, the forming support is an annular die for supporting the glass sheet in the peripheral region.

Preferably, during step (v) the glass sheet is pressed between the first mold part and the forming support in the peripheral region. When the forming support comprises at least one rail for supporting the glass sheet around its peripheral region, preferably during step (v), in the peripheral region of the glass sheet, between the first mold part and the forming support The glass sheets are pressed between at least one forming track.

Preferably, during step (vi), the glass sheet is pressed in the central region of the glass sheet at the same time as the glass sheet is pressed between the first mold part and the forming support. When the forming support comprises at least one rail for supporting the glass sheet around the peripheral region of the glass sheet, preferably during step (vi) the glass is formed between the first mold part and the at least one forming rail of the forming support. Simultaneously with the sheet pressing, the glass sheet is pressed in the central region of the glass sheet.

Preferably, the first mold part has a shaping surface and during step (v) the glass sheet faces the shaping surface of the first mold part. Preferably, the first mold part has at least one opening in its forming surface, the at least one opening in the forming surface of the first mold part being in fluid communication with at least one vacuum source, the at least one vacuum source being operable after step (vii) , providing at least one region of negative pressure in a portion of the first region of the glass sheet. At least one vacuum source in fluid communication with at least one opening in the forming surface of the first mold part may also be used to vacuum the first region of the glass sheet during at least one of steps (v), (vi) and (vii). One portion provides at least one negative pressure zone. The at least one opening in the forming surface of the first mold part may also be in fluid communication with a fluid source, such as compressed air, such that after step (vii) at least one negative pressure region is provided in a part of the first region of the glass sheet, which may then be A fluid is flowed through at least one opening in the forming surface of the first mold part.

Preferably, the second mold part has a shaping surface and during step (vi) the glass sheet faces the shaping surface of the second mold part. Preferably, the second mold part has at least one opening in its forming surface, the at least one opening in the forming surface of the second mold part being in fluid communication with at least one vacuum source, the at least one vacuum source being operable after step (vii) , providing at least one negative pressure zone in a portion of the second zone of the glass sheet. At least one vacuum source in fluid communication with at least one opening in the forming surface of the second mold part may also be used to vacuum the second region of the glass sheet during at least one of steps (v), (vi) and (vii). One portion provides at least one negative pressure zone. The at least one opening in the forming surface of the second mold part may also be in fluid communication with a fluid source, such as compressed air, such that after step (vii) at least one negative pressure region is provided in a part of the second region of the glass sheet, which may then be A fluid is flowed through at least one opening in the forming surface of the second mold part.

Preferably, the press bending device is configured such that there is at least one (first) gap between the first mold part and the second mold part. Preferably, the first gap is in fluid communication with at least one vacuum source operable to provide at least one region of negative pressure in a portion of the glass sheet opposite the first gap, the portion of the glass sheet opposite the first gap being Between the first region and the second region of the glass sheet. The first gap may also be in fluid communication with a source of fluid, such as compressed air, such that after step (vii) at least one region of negative pressure is provided in a portion of the glass sheet opposite the first gap, fluid may then flow through the first gap .

By applying negative pressure to one or more selected regions of the glass during glass bending, the glass bending process can be improved as eg described in WO2005000026A1 and WO2009002375A1. Typically, after the negative pressure is applied to one or more selected regions of the glass during glass bending, air (i.e., compressed air) is blown through openings in the forming surface in contact with the glass sheet after the source of the negative pressure is stopped to Assists in removing the glass sheet from the forming surface.

Preferably, the first mold part has a forming surface with at least one opening therein, the second mold part has a forming surface with at least one opening therein, at least one vacuum source and the first mold part The at least one opening in the forming surface is in fluid communication with the at least one opening in the forming surface of the second mold part, wherein after step (vii), at least one vacuum source is used to provide at least one regions of negative pressure, and at least one region of negative pressure is provided in a portion of the second region of the glass sheet.

Preferably, the first mold part has a mold part enclosure such that during step (v) the mold part enclosure of the first mold part is between the first mold part and the glass sheet. Preferably, the mold part cover of the first mold part comprises a fabric, more preferably a breathable fabric. Preferably, the fabric comprises at least one of stainless steel, fiberglass, parylene terephthalamide fibers or mixtures thereof, polybenzoxazole (PBO) fibers containing graphite, and various weaves of these fibers . Typically, when the first mold part has a mold part shield, the mold part shield of the first mold part is between the first mold part and the glass sheet during steps (v), (vi) and (vii).

Preferably, the second mold part is provided with a mold part enclosure such that during step (v) the mold part enclosure of the second mold part is between the second mold part and the glass sheet. Preferably, the mold part cover of the second mold part comprises a fabric, more preferably a breathable fabric. Preferably, the fabric comprises at least one of stainless steel, fiberglass, parylene terephthalamide fibers or mixtures thereof, polybenzoxazole (PBO) fibers containing graphite, and various weaves of these fibers . Typically, when the second mold part has a mold part shield, the mold part shield of the second mold part is between the second mold part and the glass sheet during steps (v), (vi) and (vii).

Preferably, the first mold part and the second mold part each have a respective mold part enclosure, and wherein the mold part enclosure of the first mold part and the mold part enclosure of the second mold part are part of a single mold enclosure. During step (v), a single mold cover faces the glass sheet. Preferably, the single mold cover comprises a fabric, more preferably a breathable fabric. Preferably, the fabric comprises at least one of stainless steel, fiberglass, parylene terephthalamide fibers or mixtures thereof, polybenzoxazole (PBO) fibers containing graphite, and various weaves of these fibers . Typically, when the first mold part and the second mold part each have a respective mold part housing, during steps (v), (vi) and (vii), the respective mold parts of the first mold part and the second mold part The hoods are respectively between the first mold part and the glass sheet and between the second mold part and the glass sheet.

Preferably, during step (vi), the second mold part is moved from the first position to the second position, the displacement of the first position of the second mold part relative to the second position of the second mold part is greater than 2 mm, preferably within 4 mm and 20mm, more preferably between 5mm and 10mm.

Preferably, during step (vi), the second mold is moved by more than 2mm relative to the first mold part, preferably between 4mm and 20mm relative to the first mold part, more preferably by 5mm relative to the first mold and between 10mm.

Preferably, the first mold part has a forming surface facing the forming support, the second mold part has a forming surface facing the forming support, and prior to step (v), the press bending device is configured such that the first mold part and the second The forming surfaces of the two mold parts are displaced from each other by more than 2mm, preferably between 4mm and 20mm, more preferably between 5mm and 10mm.

During step (iii), the glass sheet is heated to a temperature at which the glass sheet is suitably softened (i.e. has a suitably low viscosity) so that it can be formed by press bending, especially by press bending between a pair of complementary forming parts . While selected regions of the glass sheet may be heated to different temperatures, it is preferred that the glass sheet be heated uniformly during step (iii).

Preferably, during step (iii) the glass sheet is heated to a temperature between 580°C and 700°C.

Preferably, the glass sheet is heated prior to positioning the glass sheet on the forming support. However, it is possible to first position the glass sheet on the forming support and then heat it. The glass sheet may be heated to a first temperature prior to positioning the glass sheet on the forming support and subsequently heated to a second temperature on the forming support.

Preferably, the glass pane is a pane in a stack of glass panes, especially a nested pair.

Preferably, after step (vii), the bent glass sheet is thermally tempered by quenching the glass sheet with a jet of cooling fluid directed against at least one major surface of the glass sheet.

Preferably, after step (vii), the curved glass sheet is laminated to another glass sheet using an interlayer structure comprising at least one sheet of interlayer material. Suitable interlayer materials include polyvinyl butyral, ethylene vinyl acetate copolymer, polyurethane, polycarbonate, polyvinyl chloride or copolymers of ethylene and methacrylic acid.

Preferably, the glass sheet is supported on an annular mold having an upper forming surface for supporting the glass sheet around at least part of its periphery.

Preferably, the first mold part is an annular ring.

Preferably, the second mold part is a monolithic mold which is at least partially arranged within the first mold part.

Preferably, the second mold part is arranged radially within the first mold part.

Preferably, the press bending device comprises more than two die parts.

Preferably, at least one of the first mold part, the second mold part and the forming support is provided with heating means.

Preferably, at least one of the first mold part and the second mold part contains at least one of ceramic, aluminium, stainless steel or iron, especially cast iron.

Preferably, the forming support is vertically aligned with the press bending device.

The method according to the first aspect of the invention may be used to bend a flat glass sheet such that the curved glass sheet is curved in one or more directions. Preferably, the radius of curvature in at least one of the one or more directions is between 300mm and 20000mm, more preferably between 1000mm and 8000mm. When the curved glass sheet is curved in two or more directions, preferably the curvatures of two of the two or more directions are mutually orthogonal.

A suitable glass composition for the glass pane is a soda lime silica glass composition.

Typical soda lime silica glass compositions are (by weight) 69 to 74% SiO ₂ , 0 to 3% Al ₂ O ₃ ; 10 to 16% Na ₂ O, 0 to 5% K ₂ O , 0 to 6% MgO, 5 to 14% CaO, 0 to 2% SO ₃ , 0.005 to 2% Fe ₂ O ₃ . The glass may also contain other additives, such as fining aids, which are usually present in amounts of up to 2%. Soda lime silica glass compositions may contain other colorants such as _Co3O4 , _NiO , and Se to give the glass a desired color when viewed in transmitted light. The transmitted glass color can be determined according to recognized standards such as BS EN410.

From a second aspect, the present invention also provides an apparatus for shaping a glass sheet, said apparatus comprising: a press bending device comprising at least two (first and second) mold parts, each each of the mold parts has a forming surface, the press bending apparatus has a first configuration, wherein the first mold part and the second mold part are configured such that the forming surface of the first mold part is aligned with the forming surface of the second mold part, to provide the press bending apparatus with a forming surface for pressing the glass sheet into a final shape when the glass sheet is supported on a forming support, and a second configuration, wherein the forming surface of the first mold part is relative to the The forming surface is displaced and the first and second mold parts are movable relative to each other; the press bending apparatus further comprises control means to control the position of the first and second mold parts during the press bending operation, the control means is configured to control the position of the first mold part and the second mold part relative to each other to carry out at least one of steps (v), (vi) and (vii) of the method of the first aspect of the invention.

Preferably, the forming surface of the first mold part has at least one opening therein, and the at least one opening in the forming surface of the first mold part is in fluid communication with at least one source of underpressure, in particular at least one source of vacuum. Preferably, after step (vii) in the method according to the first aspect of the invention, the control means also controls at least one source of underpressure to generate at least one underpressure region in at least one opening in the forming surface of the first mold part. Preferably, during at least one of steps (v), (vi) and (vii) of the method according to the first aspect of the invention, the control means also controls at least one source of negative pressure for forming the first mold part At least one opening in the surface creates at least one negative pressure region.

Preferably, the forming surface of the second mold part has at least one opening therein, and the at least one opening in the forming surface of the second mold part is in fluid communication with at least one source of underpressure, in particular at least one source of vacuum. Preferably, after step (vii) in the method according to the first aspect of the invention, the control means further controls at least one source of underpressure to generate at least one area of underpressure in at least one opening in the forming surface of the second mould. Preferably, during at least one of steps (v), (vi) and (vii) of the method according to the first aspect of the present invention, the control means also controls at least one source of negative pressure to create pressure on the forming surface of the second mould. At least one opening in generates at least one negative pressure region.

Preferably, the press bending device is configured such that there is at least one (first) gap between the forming surface of the first mold part and the forming surface of the second mold part when the press bending device is in the first configuration, more preferably , wherein the first gap is in fluid communication with at least one negative pressure source, especially a vacuum source. Preferably, after step (vii) in the method according to the first aspect of the present invention, the control means further controls at least one negative pressure source to generate at least one negative pressure region in the first gap. Preferably, during at least one of steps (v), (vi) and (vii) in the method according to the first aspect of the present invention, the control means also controls at least one source of negative pressure to generate at least one negative pressure in the first gap Negative pressure area.

Preferably, at least one of the first mold part and the second mold part contains at least one of ceramic, aluminium, stainless steel or iron, especially cast iron.

Preferably, the first mold part is an annular ring.

Preferably, the second mold part is a monolithic mold which is at least partially arranged within the first mold part.

Preferably, the second mold part is arranged radially within the first mold part.

Preferably, the first mold part is an annular ring and the second mold part is arranged radially within the first mold part.

Preferably, the forming surface of the first mold part and/or the second mold part comprises a fabric, preferably a breathable fabric. Preferably, the fabric comprises at least one of stainless steel, fiberglass, parylene terephthalamide fibers or mixtures thereof, polybenzoxazole (PBO) fibers containing graphite, and various weaves of these fibers .

Preferably, at least one of the first mold part and the second mold part is provided with heating means.

From a third aspect, the invention provides an assembly comprising a press bending device according to the second aspect of the invention and a forming support for supporting a glass sheet thereon.

Preferably, the bending device is arranged vertically relative to the forming support.

Preferably, the press bending device is aligned with the forming support.

Preferably, in the first configuration, the forming support has an upper forming surface, and the upper forming surface of the forming support is complementary to the forming surface of the press bending device.

Preferably, the forming support has a concave upper forming surface.

Preferably, the forming support is an annular mold having an upper forming surface for supporting the glass sheet around at least part of its periphery.

Preferably, the assembly has at least three configurations: a first configuration of the assembly in which the press bending device is in a first configuration and is spaced a first distance relative to the forming support; a second configuration of the assembly in which the press bending device is in a second configuration and a third configuration of the assembly, wherein the press bending device is in a third configuration, wherein the first mold part is aligned with the forming surface of the second mold part, but the press bending part is spaced a second distance apart from the forming support, the second distance different from the first distance. Preferably, the first configuration is the same as the second configuration.

In use, the assembly is preferably configured such that the bending means is arranged vertically relative to the support.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings (not to scale), in which:

Figure 1 shows a schematic side view of a press bending station in a first configuration for bending a glass sheet;

Figure 2 shows a schematic isometric view of a two-part press-bent part in a first configuration;

Figure 3 shows a schematic isometric view of the two-part press-bending part of Figure 2 in a second configuration;

Figure 4 shows a schematic isometric view of the two-part press-bending member shown in Figure 3 in spaced relationship to the lower support frame;

Figure 5 shows a schematic view of an enlarged portion of the press bending station shown in Figure 1;

Figure 6 shows a schematic side view of the press bending station of Figure 1 in a second configuration;

Figure 7 shows a schematic side view of the press bending station of Figure 1 in a third configuration, with the first and second parts of the two-part press bending part not moved to the final bending position;

Figure 8 shows a schematic side view of the press bending station of Figure 1 in a fourth configuration, wherein the first and second parts of the two-part press bending part have been moved to a final bending position;

Figure 9 shows a schematic side view of the press bending station of Figure 1 in a fifth configuration, wherein the first and second parts of the two-part press bending part are in the same configuration as Figures 7 and 8, but both have been moves vertically and shows the curved glass sheet supported on the forming surface of the two-part press-bending part;

Figure 10 shows an enlarged schematic view of a portion of the bending station shown in Figure 1 with the glass plate on the lower support;

Figure 11 shows an enlarged schematic view of a portion of the press bending station shown in Figure 10 after the two-part press bending member has been moved downward to contact the glass sheet at its central region;

Figure 12 shows an enlarged schematic view of a part of the bending station shown in Figure 6;

Figure 13 shows an enlarged schematic view of a part of the bending station shown in Figure 7;

Figure 14 shows an enlarged schematic view of a part of the bending station shown in Figure 8;

Figure 15 shows a schematic side view representing a glass bending line incorporating the bending station shown in Figure 1;

Figure 16 is a graph showing (for the first embodiment) the vertical position of the forming surfaces of the first and second parts of a two-part press-bent part as a function of time;

Figure 17 is a graph showing the vertical position of the forming surfaces of the first and second parts of the two-part press-bending part as a function of time as shown in Figure 16, but with an expanded axis;

Figure 18 is a graph showing (for a second embodiment) the vertical position of the forming surfaces of the first and second parts of a two-part press-bent part as a function of time;

Figure 19 is a graph showing the vertical position of the forming surfaces of the first and second parts of the two-part press-bent part as shown in Figure 18 as a function of time, but with an expanded axis;

Figure 20 shows a schematic side view of a press bending station similar to that shown in Figure 8, but with a single piece of fabric covering the first and second mold parts of the two-part press bending part; and

Figure 21 shows a schematic side view of a press bending station similar to that shown in Figure 8, but with a first fabric covering the first mold part of the two-part press bending part and a second mold covering the two part press bending part A different second fabric for the part.

Figure 1 shows a schematic side view representing a press bending station 1 for bending glass sheets. The bending table 1 comprises a lower part 3 and an upper part 5 .

The lower part 3 of the bending table 1 comprises forming supports for supporting the glass sheet thereon. In this example the forming support is a frame 7 with a base 9 with first and second uprights 11 , 13 extending upwards from the base 9 . A lower support 15 in the form of an annular ring is mounted on the first and second uprights 11 , 13 . The lower support 15 has an upper forming surface 15a for supporting a glass sheet thereon, as is conventional in the art, i.e. a glass sheet (not shown) is supported on the upper forming surface 15a of the lower support 15 around its peripheral region superior.

Generally, in the art, the lower part 3 is called a curved frame or a concave curved frame. Instead of a substantially annular support ring 15 , full contact supports can be mounted on the ends of the uprights 11 , 13 .

In the example of FIG. 1 , the upper forming surface of the lower support 15 is concave. The lower support 15 may also be called a "shaping track", or simply a "track".

Although only two uprights 11 , 13 are shown in FIG. 1 , in practice there may be a plurality of uprights on which the lower support 15 is mounted.

The upper part 5 of the press bending station 1 comprises a press bending device comprising a two-part press bending part 6 comprising a first mold part 17 and a second mold part 19 . Examples of two-part molds of this type are described in US5,122,177, WO2012166365A1 and US2015/0007612A1.

With further reference to FIGS. 2 , 3 , 4 and 5 , the first mold part 17 is an annular ring having a lower forming surface 21 . The second mold part 19 is a one-piece mold part that fits inside the central opening of the first mold part 17 such that the second mold part 19 is vertically movable relative to the first mold part 17 . The second mold part 19 is arranged radially within the first mold part 17 .

The first mold part 17 has an outer peripheral wall 18a and an opposite inner peripheral wall 18b. The second mold part 19 has a peripheral wall 20 . The outer peripheral wall 20 of the second mold part 19 faces the inner peripheral wall 18b of the first mold part 17 and is spaced apart from the inner peripheral wall 18b of the first mold part 17 by a gap 40 . In the cross-sectional view of FIG. 1 , gap 40 is represented by two gaps 39 and 41 .

The second mold part 19 has a lower forming surface 23 . The forming surfaces 21, 23 are configured so that when the glass sheet is supported on the frame 7, i.e. on the upper forming surface 15a of the support 15 and when the first and second mold parts are in a certain predetermined configuration, The desired curvature of the glass sheet is provided in those regions of the glass sheet that are to be contacted by the shaping surfaces 21 , 23 .

As shown more clearly in Fig. 4, the lower support 15 is mounted on one side on the uprights 11, 11' and 11"' and on the opposite side on the uprights 13, 13' and 13". Uprights 11 , 11 ′, 11 ″, 13 , 13 ′, 13 ″ extend upwardly from the base 9 and are connected to the base 9 at one end and to the lower support 15 at the opposite end. Additional uprights may be used. It is also possible to use reinforcing beams between the columns.

With further reference to FIG. 5, when the outer peripheral edge 20a of the second mold part 19 is aligned with the inner peripheral edge 18c of the first mold part 17, the two-part press-bending part 6 has a forming surface corresponding to the desired final forming surface, such as As indicated by dotted line 24. In this example, the forming surface of the two-part press-bent part 6 is a convex forming surface configured to be complementary to the upper forming surface 15 a of the lower support 15 . The desired final forming surface 24 is shown in dashed line 25 in the final desired position for forming the glass sheet supported on the upper forming surface 15a of the lower support 15 into the final desired shape.

Referring to Figures 1 and 5, the first mold part 17 is displaced relative to the second mold part 19 such that the forming surface of the two-part press-bending part is not the desired final forming surface of the two-part press-bending part. The outer peripheral edge 20 a of the second mold part 19 is displaced by an amount 43 from the inner peripheral edge 18 c of the first mold part 17 .

The first mold part 17 is movable in the vertical direction (shown by arrow 30 ) by means of linear actuators 31 and 33 . The movement of the linear actuators 31, 33 is synchronized such that both sides of the first mold part 17 move up and down simultaneously.

The second mold part 19 is movable in a vertical direction 30 by means of a linear actuator 35 .

Both the first mold part 17 and the second mold part 19 are independently movable relative to each other in the vertical direction.

The linear actuators 31 , 33 and 35 are mounted on a suitable frame 37 which is spatially fixed relative to the frame 7 .

Movement of the linear actuators 31, 33 and 35 may be controlled by suitable control means such as a computer based system (not shown).

In the configuration shown in FIG. 1 (and FIG. 5 , which is an enlarged view of a portion on the left-hand side of FIG. 1 ), the forming surface 21 of the first mold part is displaced on one side from the final desired position indicated by the dotted line 25 The vertical distance 27 is displaced on the other side by a vertical distance 27 ′ from the final desired position indicated by the dotted line 25 . Preferably distance 27 is the same as 27'.

The forming surface 23 of the second mold part 19 is displaced a vertical distance 29 from the final desired position indicated by the dotted line 25 .

As discussed above, the press bending station 1 is shown in FIG. 1 in a first configuration with the forming surface 23 displaced relative to the forming surface 21 by an amount 43 . Due to the displacement 43, the two-part mold 6 is not configured to bend the glass sheet supported on the frame 7 into the final desired shape.

In FIG. 1 , two gaps 39 , 41 between the inner peripheral wall 18 b of the first mold part 17 and the outer peripheral wall 20 of the second mold part 19 are shown. These two gaps 39 , 41 are part of a continuous gap 40 extending between the first mold part 17 and the second mold part 19 , as exemplified in FIGS. 2 to 4 . Gap 40 may be in fluid communication with a suitable vacuum source to assist in shaping the glass sheet by providing an area of negative pressure in the gap. As can be seen, the gap 40 extends to the forming surface of the two-part press bent part 6 .

FIG. 6 shows the press bending station 1 in a different configuration than that shown in FIG. 1 . In this second configuration, the glass pane 50 has already been positioned on the frame 7 and is en route to the bending process according to the invention. The glass plate 50 has a main surface 52 facing the two-part press-bending part 6 and an opposite main surface 54 facing the base 9 (and thus the frame 7 and the lower support 15 ). The major surface 54 of the glass sheet 50 is in contact with the upper forming surface 15a (not labeled in this figure, but see Figure 1 ) of the lower support 15 .

Starting from the configuration shown in FIG. 1 , both the first mold part 17 and the second mold part 19 are moved downwards towards the frame 7 by energizing the respective linear actuators 31 , 33 and 35 . The downward movement of both the first mold part 17 and the second mold part 19 is synchronized such that the first mold part 17 and the second mold part 19 move downward without relative movement between them.

The downward movement of the first mold part 17 and the second mold part 19 towards the frame 7 may be one or more stages, with or without relative movement between the first mold part and the second mold part in each stage. In one example, in the first stage of downward movement, the downward speed of the first mold part and the second mold part is a first speed u1, and the second downward movement after the first stage of downward movement In phase, the downward speed of the first mold part and the second mold part is a second speed u2. Preferably u1>u2, so that the first mold part 17 and the second mold part 19 move faster in the first phase of downward movement than in the second phase of downward movement.

Referring to FIGS. 1 and 6 , in a second configuration as shown in FIG. 6 , the forming surface 21 of the first mold part 17 is already in contact with the main surface 52 of the glass sheet 50 in the peripheral region of the glass sheet 50 . Due to the specific configuration of the first mold part 17 and the second mold part 19 , the forming surface 23 of the second mold part 19 is also already in contact with the second main surface 52 of the glass pane 50 in the central region of the glass pane 50 . This central area is inside the peripheral area of the glass pane. The final desired position of the first mold part 17 and the second mold part 19 has not yet been reached.

In FIG. 7 , the press bending station 1 is shown in another configuration than that shown in FIGS. 1 and 6 . Prior to this configuration, the press bending table 1 was in the configuration shown in FIG. 6 .

In this third configuration shown in FIG. 7 , the second mold part 19 has been moved downwards by energizing the linear actuator 35 so that the forming surface 23 of the second mold part 19 is further in the central region of the glass sheet. Contact is made with the major surface 52 of the glass sheet 50 to press bend the central region of the glass sheet 50 . In this example, the forming surface 23 is shown aligned with the forming surface 21 (with reference to Figure 5, such that the displacement 43 is zero).

In this third configuration, the first mold part 17 and the second mold part 19 are not reached even though they are configured to provide the two-part press bending part 6 with the final desired forming surface. final desired position. Referring to FIG. 5 , displacement 43 is zero, but both vertical distance 27 and vertical distance 29 are greater than zero because forming surface 21 and forming surface 23 have not yet reached the final position indicated by dotted line 25 .

The first mold part 17 and the second mold part 17 can be reached by moving the first mold part 17 and the second mold part 19 further down towards the frame 7 to press bend the glass sheet 50 further in the peripheral and central regions of the glass sheet. Final desired position of part 19. In this example, there is no relative movement between the first mold part and the second mold part when moving towards their final desired position, so that during this further moving step, the forming surface 23 remains aligned with the forming surface 21 . This is further described with reference to Figure 8, although due to the scale of the drawing it is difficult to show the different configurations.

In a fourth configuration shown in FIG. 8 , the forming surface 21 of the first mold part 17 is aligned with the forming surface 23 of the second mold part 19 . Referring to Figure 5, displacement 43 is zero. In this configuration, the two-part press bending part 6 has pressing surfaces for pressing the glass sheet 50 supported on the frame 7 into the final desired shape, and the press bending is configured such that the desired shape of the two-part press bending part 6 The forming surface is also in the desired position. Referring to FIG. 5 , in this fourth configuration both the forming surface 21 and the forming surface 23 lie on the dashed line 25 . Starting from the configuration shown in FIG. 7, both the first mold part and the second mold part are moved simultaneously to the desired final position, so that the forming surfaces 21, 23 move from the configuration shown in FIG. Alignment is maintained during construction moves.

In the configuration shown in FIG. 8, the gaps 39, 41 are in fluid communication with a vacuum source (not shown) to provide negative pressure at the major surface 52 of the glass sheet 50, at least in the vicinity of the glass sheet facing the gaps 39, 41. area.

The vacuum source may apply vacuum to gaps 39 , 41 for any desired time to improve bending of glass sheet 50 . The vacuum source is preferably applied to the gaps 39, 41 after the press bending table has reached the fourth configuration described above. The vacuum may be applied in stages, with a different level of vacuum applied in one stage compared to another. The duration of the vacuum phases can be the same or different. The vacuum duration in one or more vacuum stages may be between 0.05 and 5 seconds.

In FIG. 9 the press bending station 1 is shown in another (fifth) configuration. In this fifth configuration, because the forming surfaces of the first mold part 17 and the second mold part 19 are aligned (displacement 43 is zero with reference to FIG. Configure in the same way. However, the configuration of the bending table 1 shown in FIG. 9 is different compared to the configuration of the bending table 1 shown in FIG. / Power on, the two-part mold 6 has been raised relative to the frame 7 . The first mold part 17 and the second mold part 19 have moved upwards towards the frame 37 at the same rate in the direction of the arrow 30', i.e. the upward movement of the first mold part 17 and the second mold part 19 towards the frame 37 is synchronous Yes, there is no relative movement between the first mold part and the second mold part.

A curved glass sheet 50 is shown supported in two parts by means of applying a vacuum across the gaps 39, 41 (and thus gap 40, see FIGS. The underside of the bending part 6.

In addition to applying a vacuum at the gaps 39, 41, the forming surface 21 of the first mold part 17 may have fluid communication therein with a vacuum source (which may be the same vacuum source as used to provide the vacuum at the gaps 39, 41). opening. A vacuum source in fluid communication with the openings in the forming surface 21 may also be used to support the glass sheet 50 on the underside of the two-part press bending part 6 .

Furthermore, in addition to applying a vacuum to the gaps 39, 41 and/or openings in the forming surface 21 of the first mold part 17, the forming surface 23 of the second mold part 19 may also have a vacuum source therein (which may be a An opening in fluid communication with the same vacuum source as the vacuum source providing the vacuum in the gaps 39, 41). A vacuum source in fluid communication with openings in forming surface 23 may also be used to support glass sheet 50 on the underside of two-part press bending part 6 .

The carrier ring 58 is shown disposed between the frame 7 (ie above the upper forming surface 15a of the lower support 15 ) and the two-part press-bending part 6 . At a suitable time for the bending operation, the vacuum applied at the gap 39, 41 (or gap 40) is terminated, so that the bent glass sheet 50 is no longer supported on the underside of the two-part press bending part 6, but falls from there. Supported by the carrier ring 58 . The gaps 39, 41 (or gap 40) may also be in fluid communication with a suitable source of fluid, such as compressed air, so that after the vacuum at the gaps 39, 41 is terminated, the fluid, i.e. compressed air, is caused to flow through the gaps 39, 41 towards the glass sheet 50 , to assist in removing the curved glass sheet 50 from the forming surfaces 21 , 23 of the respective first mold part 17 and second mold part 19 .

A suitable actuator (not shown) is provided to move the carrier ring 58 in the direction of arrow 60 away from between the frame 7 and the two-part press-bending part 6 . Thereafter, the bent glass sheet may be placed on a suitable conveyor (not shown) for subsequent annealing or tempering.

As discussed above, although not shown in the figures, the forming surface 21 of the first mold part 17 and/or the forming surface 23 of the second mold part 19 may have at least one opening therein which communicates with at least A source of negative pressure, such as a vacuum source, is in fluid communication.

The or each opening in the forming surface 21 of the first mold part 17 and/or the or each opening in the forming surface 23 of the second mold part 19 may have Additional negative pressure areas for improved shape control when bending glass sheets.

If the forming surface 21 of the first mold part 17 has one or more openings therein for providing a vacuum (e.g., as described above with respect to the gaps 39, 41), any number of the openings in the forming surface 21 It may also be in fluid communication with a suitable source of fluid, such as compressed air, to assist in the removal of the curved glass sheet from the forming surface 21 by flowing the fluid through the openings towards the glass sheet after the vacuum is terminated.

Likewise, if the forming surface 23 of the second mold part 19 has one or more openings therein for providing a vacuum (e.g., as described above with respect to gaps 39, 41), any number of openings in the forming surface 23 The openings may also be in fluid communication with a suitable fluid source, such as compressed air, to assist in removing the curved glass sheet from the forming surface 23 by flowing fluid through the openings towards the glass sheet after the vacuum is terminated.

To further illustrate the sequence of movement of the first mold part 17 and the second mold part 19 during the forming process according to the invention, the left hand parts of Figures 1 (except for the glass plate 50 on the frame 7), 6, 7 and 8 have been enlarged and provided as an attached figure. These enlarged portions of the above figures are shown in Figures 10, 12, 13 and 14, respectively. 11 is included to illustrate that during the forming operation, before the forming surface 21 of the first mold part 17 comes into contact with the glass sheet 50 in the peripheral region of the glass sheet 50, when the forming surface 23 of the second mold part 19 is placed on the glass The moment when the central region of the plate 50 comes into contact with the glass plate 50 .

Referring to FIGS. 1 and 10 , a glass sheet 50 is shown supported on the forming surface 15 a of the lower support 15 . The glass sheet has been suitably positioned on the forming surface 15a using methods known in the art. Glass sheet 50 has a first major surface 52 and an opposing second major surface 54 . The second main surface 54 is in contact with the upper forming surface 15 a of the lower support 15 . The glass pane has been softened by heat and can sag slightly in its central region.

A portion of the two-part press bent part 6 , labeled 6 ′, is shown positioned above the glass sheet 50 . The first mold part 17 has a forming surface 21 facing the first major surface 52 of the glass sheet 50 and the second mold part 19 has a forming surface 23 facing the first major surface 52 of the glass sheet 50 .

As mentioned above, because the edges 18c and 20a are misaligned, the forming surfaces 21, 23 are offset by a displacement 43 from each other.

As shown in the figure, neither the molding surfaces 21 , 23 are in contact with the glass plate 50 .

In FIG. 11, both the first mold part 17 and the second mold part 19 have been moved downward together so that there is no relative movement between them, i.e. starting from the configuration shown in FIG. 10, the first mold part 17 and Both second mold parts 19 move along arrow 30 at the same speed. In this way, the forming surfaces 21, 23 are still misaligned and there is still the displacement 43 described above (in this case the displacement 43 is the same as in Fig. 10). In this configuration, the forming surface 23 is just in contact with the first major surface 52 of the glass sheet 50 . However, because of the particular configuration of the first mold part 17 and the second mold part 19 of the two-part press bending part 6', the position of the first mold part 17 relative to the second mold part 19 is such that the forming surface 21 has not yet joined the surface of the glass sheet 50. First major surface 52 is in contact (even though forming surface 23 is already in contact with first major surface 52 of glass sheet 50).

Different configurations of the first mold part 17 and the second mold part 19 of the two-part press bending part 6' can be used, wherein the second mold part 19 is arranged relative to the first mold part 17 such that the forming surface of the second mold part 19 The forming surface 21 of the first mold part 17 is in contact with the first major surface 52 of the glass sheet prior to contact 23 with the first major surface 52 of the glass sheet. In this alternative embodiment, the location of the second mold part is shown in imagery as 19a with forming surface 23a. It will be apparent that the first mold part and the second mold part may be configured such that when the first mold part and the second mold part move downwardly towards the frame at the same speed, their respective forming surfaces simultaneously contact with the surface of the glass sheet 50. The first major surface 52 is in contact.

FIG. 12 is an enlarged view of a part of the left hand side of FIG. 6 showing that the glass sheet 50 is partially pressed between the first forming part 17 and the lower support 15 in its peripheral region. Since both the first mold part and the second mold part have continued to move downward (in the direction of arrow 30) at the same speed (when starting with the configuration shown in Figures 10 or 11), the glass sheet 50 is also in its The central region is lightly pressed by the second mold member 19 . However, as mentioned above, the forming surfaces of the first and second mold parts still have a non-zero displacement 43 .

Figure 13 is an enlarged view of a part of the left hand side of Figure 7 showing the two-part press bending part 6' after the configuration shown in Figure 12, wherein the first mold part 17 remains stationary relative to the lower support 15, The second mold part 19 has been moved further downwards (in the direction of the arrow 30 ) to press-bend the glass sheet 50 in its central region. By partial pressing between the first mold part 17 and the lower support 15 , the glass pane 50 is adequately held in its peripheral region. In this configuration, there is no displacement between the forming surfaces 21 , 23 of the first mold part 17 and the second mold part 19 (displacement 43 is zero). Thus, the two-part press bender 6' has the desired final shaped surface, but the two-part press bender is not in the final position to fully press bend the glass sheet 50 into the desired shape. This is shown in Figure 14 below.

Figure 14 is an enlarged view of a portion of the left hand side of Figure 8 showing the two-part press bending part 6' after the configuration shown in Figure 13, wherein both the first mold part 17 and the second mold part have been simultaneously Downward movement (in the direction of arrow 30 ), ie there is no relative movement between the first mold part 17 and the second mold part 19 . Again, there is no displacement between the forming surfaces of the first mold part and the second mold part (displacement 43 is zero). The two-part press bending part 6' has the desired final forming surface (since the displacement 43 is zero) and has been moved to the final position (see dotted line 25 in Figure 5) to fully press bend the glass sheet 50 into the desired shape. After this final bending step, a vacuum can be generated in gap 39 (and gap 41, see FIG. 8 ) to hold glass sheet 50 on the underside of two-part mold 6' and improve shape control of the bent glass sheet, as above.

FIG. 15 shows a schematic cross-sectional view representing part of a glass bending line 70 incorporating a bending station 1 of the type shown in FIG. 1 , the operation of which is described with reference to FIGS. 1 to 14 .

The glass bending line 70 includes a furnace 72 , a press bending section 74 which may or may not be heated, and an annealing furnace 76 .

Roller conveyor bed 78 extends through furnace 72 , press bend 74 , and lehr 76 to define a conveyor path for glass sheet 50 . The roller conveyor bed includes a plurality of rollers 80 configured (in spaced parallel relationship) to convey glass sheet 50 in the direction of arrow 82 . In this example, the glass sheet 50 is shown in contact with the rollers 80 , but the glass sheet 50 could be positioned on a suitable carriage (not shown), which is in contact with the rollers 80 . As an alternative to or in addition to rollers 80 , an air flotation device may be used to transport the glass sheet in the direction of arrow 82 .

In the furnace 72, the glass sheet 50 is heated to a temperature suitable for bending. The furnace may incorporate any suitable heating means, such as electric, gas, convective, and microwave heating, and combinations thereof, as desired.

Inside the press bending unit 74 is the press bending table 1 . When the glass sheet 50 is transferred between the frame 7 and the two-part press bending part 6, it is positioned on the frame 7 for subsequent press bending by placing the glass sheet on the frame 7, as already referred to in FIG. to 14 described. Methods are known in the art for transferring glass sheets from the transfer rollers 80 to the frame 7, for example, some transfer rollers may be configured as drop rollers, or a vacuum table may be used to transfer the heat softened glass sheets from the transfer rollers. to be placed on a suitably constructed frame 7.

15 and FIG. 1, the two-part press-bending part 6 is shown in electrical communication with a control device 84, such as a computer, for controlling the first part of the two-part press-bending part 6 by means of the linear actuators 31, 33, 35. Relative movement of the mold part 17 and the second mold part 19 . Control device 84 may be in electrical communication with other portions of glass bending line 70 , such as transfer roller bed 78 , to control the speed of rollers 80 and/or actuators (not shown) that control movement of carrier ring 58 .

Carrier ring 58 is shown between press bend 74 and lehr 76 and can be brought into the position shown in FIG. Move between the positions shown in Figure 15. The curved glass sheet supported by the carrier ring 58 is moved from between the two-part press bending part 6 and the frame 7 (i.e., inside the press bending part 74) to the outside of the pressing bending part 74, where the curved glass sheet can then be moved. The glass sheet is placed on section 78' of roller transfer bed 78 for transfer to lehr 76 for subsequent annealing, ie controlled cooling to ambient temperature.

Although in the figures the two-part press bending part 6 is shown with exposed forming surfaces 21 and 23 as previously described herein, in a preferred embodiment one or the other of the first mold part 17 and the second mold part 19 Both can be provided with protective covers to protect the forming surfaces of the mold parts from damage and wear. The lower support 15 may also be provided with such a protective cover to cover the upper forming surface 15a. When using a shroud, preferably, the shroud comprises a material made of, for example, stainless steel, fiberglass, polyphenylene terephthalamide fibers (e.g., Kevlar ^™ ), mixed Kevlar ^™ materials, polybenzoxazole (PBO ) fibers (eg, Zylon ^™ ) or various weaves of these fibers.

If a protective cover is used to cover each forming surface 21, 23, a single cover covering both forming surface 21 and forming surface 23 is preferably used.

If a protective cover covering both forming surfaces 21 and 23 is used, the protective cover should be sufficiently flexible to allow movement of the first and second mold parts as previously described herein.

Furthermore, if a protective cover is used covering both forming surfaces 21 and 23, it is preferred that the protective cover is sufficiently porous or breathable to allow a vacuum to be provided therethrough, for example between a first mold part and a second mold part. The gap 40, or any opening in the respective forming surfaces of the first mold part and the second mold part as previously described, provides a vacuum.

A separate protective cover may be used for each of the forming surfaces 21 , 23 . This has the advantage that the gap between the first mold part and the second mold part is not obstructed by the material of the protective cover.

Moving between the configurations shown in Figures 1, 6, 7 and 8 (or Figures 10 to 14) is illustrated in Figures 16, 17 (for the first example) and in Figures 18 and 19 (for the second example) The downward movement of the first mold part 17 and the second mold part 19. Figures 16 to 19 show the vertical position of the first mold part 17 and the second mold part 19 relative to the final desired position of the forming surfaces of the parts indicated by line 25 in Figures 1 and 5 .

In Figures 16 to 19, axis 90 is time in seconds and axis 92 is distance in mm.

In FIGS. 16 and 17 , dashed lines indicate the vertical displacement of the forming surface 21 of the first mold part 17 relative to the final desired position of said forming surface 21 . The solid line represents the vertical displacement of the forming surface 23 of the second mold part 19 relative to the final desired position of said forming surface 23 . The final desired position of the forming surfaces 21, 23 (when they are aligned, see Figures 5, 7 and 13 and their associated descriptions) is at a vertical displacement of -200mm relative to a reference point of zero. At time=zero the forming surface 21 is at a reference point of zero and at time=zero the forming surface 23 is at +10 mm relative to the reference point of zero. That is, at the final desired position of the forming surface 21 the total vertical movement downwards is 200 mm, while for the forming surface 23 the total vertical movement downwards is 210 mm.

Referring to Figures 16 and 17, the relative movement of the first mold part 17 and the second mold part 19 in the first embodiment will be described.

At time t=0 (ie points A and A'), the two-part press bending die 6 is configured such that the forming surface 21 of the first die part 17 is displaced by 10 mm relative to the forming surface 23 of the second die part 19 . Referring to Figure 5, distance 27 (and thus distance 27', see Figure 1) is 200mm, distance 29 is 210mm, and displacement 43 is 10mm.

After 0.5 seconds (at points B, B'), the press bending operation starts, both the first mold part 17 and the second mold part 19 are moved vertically downwards towards the glass sheet 50 supported on the frame 7, see e.g. Fig. 10 . Both the first mold part 17 and the second mold part 19 move downward at the same speed (= v1 ), so during this downward movement phase, the forming surface 21 of the first mold part 17 and the second mold part 19 , 23, ie, at points B-C and B'-C', the movement of the first mold part 17 and the second mold part 19 is synchronous, and the displacement 43 remains fixed at 10 mm.

After 1.2 seconds (at points C, C'), when approaching the surface of the glass sheet 50, the descending speed of the first mold part 17 and the second mold part 19 decreases (to speed v2). The synchronized vertical downward movement of the first mold part 17 and the second mold part 19 continues at speed v2 until point D, D' is reached.

After 2.1 seconds (at point D), the second mold part 19 continues to move vertically downwards at speed v2. However, at point D' (which coincides in time with point D), the vertical downward movement of the first mold part 17 stops. The bending station is in the configuration shown in Figure 6 (or Figure 12). At this point in time, the main surface 52 of the glass sheet 50 has been contacted by the forming surface 21 of the first mold part 17, so that the glass sheet 50 is partially pressed between the lower support 15 of the frame 7 and the first mold part 17 .

During the next 0.2 seconds, the second mold part 19 continues to move downwards at a speed v2 to press-bend the glass sheet 50 in the central region of the glass sheet 50 while the glass sheet 50 remains stationary with the first mold part 17 partially suppressed. That is, between points D' and E', the first mold part 17 remains stationary relative to the frame 7 to partially press the glass sheet in its peripheral region.

After 2.3 seconds (at point E'), the movement of the first mold part 17 resumes at a selected downward velocity (=v3) so that both the first mold part 17 and the second mold part 19 reach the final desired position simultaneously. position (at points F, F'). That is, the second mold part 19 continues to move vertically downward with velocity v2 between points E and F, while the first mold part moves vertically downward with velocity v3 between points E' and F'.

The downward movement of the first mold part 17 between points E' and F' further compresses the peripheral region of the glass sheet between the upper forming surface 15a of the lower support 15 and the forming surface 21 of the first mold part. That is, in the peripheral region, the glass sheet is pressed further between the lower support 15 and the first mold part 17 , while the glass sheet is further bent by the second mold part 19 in the central region.

Clearly, as the second mold part 19 continues to move vertically downwards between points D and E, since the first mold part 17 is stationary between points D' and E' (which correspond to points D and E, respectively) Therefore, the distance between the forming surfaces 21, 23 of the first mold part 17 and the second mold part 19 is reduced. Referring to FIG. 5 , the displacement 43 decreases between points D and E .

After 2.5 seconds (at points F, F'), both the first mold part 17 and the second mold part 19 have reached the final desired position and press bend the glass sheet 50 into the final desired shape. The bending station is in the configuration shown in FIG. 8 or FIG. 14 . At points F, F' the forming surface of the two-part curved part 6 has the final desired curvature.

In this particular example of the method according to the first aspect of the invention (as illustrated in Figures 16 and 17), the initial separation (displacement 43) of the forming surfaces of the first and second pressing is 10mm. The first mold part 17 is moved vertically downwards to a position such that the position of the forming surface 21 is 2 mm from the final position of the forming surface 21 . The forming surfaces 21, 23 are then moved as described above to simultaneously reach the final position indicated by points F, F, which is two days after the initial vertical downward movement of both the first mold part 17 and the second mold part 19 has begun. seconds, that is, two seconds after point B, B'.

By stopping the first mold part 17 at point D' and then restarting the downward movement of the first mold part at point E', it was found that further downward movement of the first mold part 17 moved the forming surface 21 to the final position while , the forming surface 23 of the second mold part 19 reaches the final position, i.e. at points F, F', compared to when the first mold part 17 is moved to the final position without a prior stop. Transient stresses developed in the plate 50 are reduced. That is, where the first mold part does not stop at point D' but continues at velocity v2 until the forming surface 21 of the first mold part 17 is at the final desired position (i.e. -200 mm from the zero datum), in press bending There was more glass breakage during operation.

Another test was performed using a modified downward movement of the first mold part 17 and the second mold part 19 .

This second example is described with reference to FIGS. 18 and 19 . In FIGS. 18 and 19 , the dashed lines indicate the vertical displacement of the forming surface 21 of the first mold part 17 relative to the final desired position of said forming surface 21 . The solid line represents the vertical displacement of the forming surface 23 of the second mold part 19 relative to the final desired position of said forming surface 23 . The final desired position of the forming surfaces 21, 23 (when they are aligned, see Figures 5, 7 and 13 and their associated descriptions) has a vertical displacement of -200mm from a reference datum point of zero. The forming surface 21 is at a reference point of zero at time=zero and the forming surface 23 is at +10 mm relative to the reference point of zero at time=zero. That is, at the final desired position of the forming surface 21, the total downward movement is 200mm, while for the forming surface 23, the total downward movement is 210mm.

In Figures 18 and 19, until point D, D' (at 2.1 seconds), the movement of the first mold part 17 and the second mold part 19 in this second example is the same as in the first example (as in Figure 16 and exemplified in 17). That is, between points B and C (and B' and C'), both the first mold part 17 and the second mold part 19 move vertically downwards at a velocity v1 (displacement 43 fixed at 10 mm), and at Between points C and D (and C' and D'), both the first mold part 17 and the second mold part 19 move vertically downwards at a velocity v2 (again, the displacement 43 is fixed at 10 mm).

In this second example, at point D, the second mold part 19 continues to move vertically downwards at the same speed v2 until at point F it reaches the final position. The second mold part 19 in this second example moves downwards in the same way as in the first example described with respect to FIGS. 16 and 17 .

As in the first example, in the second example, when the first mold part reaches point D (after 2.1 seconds), its downward movement stops. However, contrary to the first example, the first mold part remains stationary until the forming surface 21 of the first mold part 17 and the forming surface 23 of the second mold part are aligned (at points G, G'). Referring to Figure 5, at points G, G' the displacement 43 is zero and the forming surfaces 21, 23 are aligned. The two-part press bent part 6 has a final desired forming surface (indicated by dotted line 24 in FIG. 5 ), but the final desired forming surface is not in the desired final position (indicated by dashed line 25 in FIG. 5 ).

At this point, when the displacement 43 is zero (which is about 2.43 seconds), at point G', the downward movement of the first mold part 17 resumes so that the forming surface 21 of the first mold part and the surface of the second mold part The forming surface 23 is moved to the final desired position.

Between points G' and F' the movements of the first mold part 17 and the second mold part 19 are synchronized again such that there is no relative vertical movement between the two forming surfaces 21 , 23 . The first mold part 17 and the second mold part 19 move vertically downwards at the same speed (=v2) until they reach a final position F, F' at a vertical distance of -200 mm from the reference reference point of zero . The forming surfaces 21, 23 are aligned and the displacement 43 is zero.

The bending device is then also in the configuration as shown in Figure 8 (and in Figure 14), but in contrast to the first example of the method (as described above with reference to Figures 16 and 17), during the bending operation The relative movement between the first mold part and the second mold part is different during this time. The second example described above is illustrated in FIGS. 10 to 14 .

This method according to the invention is useful for bending an initially flat glass sheet to a final curvature for use as a curved glass sheet for automobiles, for example as a layer in a windshield, or as a side window, rear window or roof window i.e. Panels for sunroofs are especially useful. Two such curved glass panes may be used in vehicle windshields, joined together by at least one layer of adhesive interlayer material such as polyvinyl butyral (PVB).

FIG. 20 shows a schematic side view of another bending station 1 ′ which is substantially identical to the bending station 1 described with reference to FIGS. In addition to the single piece of fabric 16 of the first mold part 17 and the second mold part 19 .

The bending table 1 ′ is shown in substantially the same configuration as the bending table 1 in FIG. 8 . However, because the first and second mold parts are covered by a single piece of fabric 16 , the forming surface of first mold part 17 is covered by fabric 16 such that fabric 16 is in direct contact with major surface 52 of glass sheet 50 . In this way, the forming surface 21 of the first mold part 17 and the forming surface 23 of the second mold part 19 are in indirect contact with the major surface 52 of the glass sheet 50 .

Preferably, fabric 16 is a breathable fabric. Preferably, fabric 16 comprises at least one of stainless steel, glass fibers, polyparaphenylene terephthalamide fibers or mixtures thereof, graphite-containing polybenzoxazole (PBO) fibers, and various weaves of these fibers. kind.

FIG. 21 shows a schematic side view of another press bending station 1 ″ which is substantially identical to the press bending station 1 described with reference to FIGS. A fabric 16 ′ and a second fabric 16 ″ covering the second mold part 19 , ie the fabric 16 ′ covers the forming surface 21 of the first mold part 17 and the fabric 16 ″ covers the forming surface 23 of the second mold part 19 . To accommodate the two fabric covers, a second mold part 19' with a slightly smaller forming surface is provided to accommodate the peripheral wall 18a and the inner peripheral wall 18b extending to the first mold part 17 and the peripheral wall 20 of the second mold part 19' fabric. Thus, the gaps 39', 41' are slightly wider than the gaps 39, 41 of FIG. Also, because two fabrics 16', 16" are used, the gaps 39' and 41' are not obstructed by the fabric near the forming surface of the two-part press bending part 106 (because the second mold part 19' is different from the two-part press bending part 106). The second mold part 19 of the bending part 6, so designated as 106).Using two or more pieces of fabric also provides an advantage that when the fabric is worn due to continuous use in bending the glass sheet, only Replacement of selected areas of fabric.When using one piece of fabric, if the fabric wears out, the entire piece of fabric needs to be replaced, when using at least the first and second fabrics, only one piece of fabric can be replaced as needed.

The bending station 1" is shown in substantially the same configuration as the bending station 1 in Figure 8. However, because the first mold part 17 is covered by the fabric 16', the second mold part 19' is covered by the fabric 16". The fabrics 16' and 16" are in direct contact with the first major surface 52 of the glass sheet 50. Like this, the forming surface 21 of the first mold part 17 and the forming surface 23 of the second mold part 19 contact the glass through the fabrics 16' and 16", respectively. The first major surface 52 of the plate 50 is in indirect contact.

Preferably, at least one of the fabrics 16', 16" is a breathable fabric. Preferably, the fabrics 16' and/or 16" comprise stainless steel, fiberglass, polyparaphenylene terephthalamide fibers or mixtures thereof, Graphite-containing polybenzoxazole (PBO) fibers and at least one of various weaves of these fibers.

It has been found that when using the method of shaping a glass sheet according to the invention, as well as improving the wrinkles in the peripheral region of the bent glass sheet (compared to using a single integral upper press bending part), the forming operations are reduced , the risk of glass breakage during the bending operation.

Although the examples provided herein refer only to a two-part press bending unit, the press bending apparatus may comprise a press bending unit with three or more independently movable mold parts, for example, during step (v), glass may be Two opposing transverse peripheral regions of the sheet are pressed, during step (vi) the central region of the glass sheet may be pressed between the two opposing transverse peripheral regions of the glass sheet.

Claims (51)

1. A method for forming a glass plate, comprising the following steps: (i) providing shaped supports for supporting the glass sheets; (ii) providing a press bending apparatus comprising at least a first mold part and a second mold part, each of the first mold part and the second mold part being movable relative to the forming support; (iii) heating the glass sheet; (iv) positioning the glass sheet on the forming support; (v) moving at least one of the forming support and the press bending device towards the other to compress the glass sheet in the first region of the glass sheet between the forming support and the first mold part; (vi) moving the second mold part relative to the first mold part to compress the glass sheet in the second region of the glass sheet, and (vii) moving the first mold part relative to the forming support to further compress the glass sheet in the first region of the glass sheet between the first mold part and the forming support, wherein the first region of the glass sheet is a peripheral region of the glass sheet, and wherein the second region of the glass sheet is a central region of the glass sheet. 2. A method according to claim 1, wherein the press bending device is in contact with the glass sheet in a second region of the glass sheet before or during step (v). 3. A method according to claim 1 or 2, wherein, during step (vii), the second mold part is moved relative to the forming support glass sheet to shape the glass sheet in a second region of the glass sheet. plate for further bending. 4. The method of claim 3, wherein during step (vii) the second mold part is also moved relative to the first mold part. 5. The method of claim 3, wherein during step (vii) the movement of the first mold part and the second mold part relative to the forming support is synchronized. 6. A method according to claim 1 or 2, wherein the forming support comprises at least one rail for supporting the glass sheet around a peripheral region of the glass sheet. 7. A method according to claim 6, wherein the forming support is an annular die for supporting the glass sheet in the peripheral region. 8. A method according to claim 6, wherein during step (v) the glass sheet is pressed between the first mold part and the forming support in the peripheral region. 9. A method according to claim 1 or 2, wherein during step (vi) the glass sheet is pressed in the central region of the glass sheet while the glass sheet is being pressed between the first mold part and the forming support. The glass sheets are pressed. 10. A method according to claim 1 or 2, wherein the first mold part has a shaping surface and during step (v) the glass sheet faces the shaping surface of the first mold part. 11. The method of claim 1 or 2, wherein the first mold part has at least one opening in its forming surface, the at least one opening in the forming surface of the first mold part is connected to at least one vacuum source In fluid communication, after step (vii), the at least one vacuum source is operable to provide at least one region of negative pressure in a portion of the first region of the glass sheet. 12. A method according to claim 1 or 2, wherein at least one opening in the forming surface of the first mold part is in fluid communication with at least one fluid source such that after step (vii) a fluid can flow through At least one opening in the forming surface of the first mold part. 13. A method according to claim 1 or 2, wherein the second mold part has a forming surface and during step (vi) the glass sheet faces the forming surface of the second mold part. 14. The method of claim 1 or 2, wherein the second mold part has at least one opening in its forming surface, the at least one opening in the forming surface of the second mold part is connected to at least one vacuum source In fluid communication, after step (vii), the at least one vacuum source is operable to provide at least one region of negative pressure in a portion of the second region of the glass sheet. 15. The method of claim 1 or 2, wherein at least one opening in the forming surface of the second mold part is in fluid communication with at least one fluid source such that after step (vii) fluid can be passed through At least one opening in the forming surface of the first mold part. 16. A method according to claim 1 or 2, wherein the press bending device is configured such that there is at least a first gap between the first mold part and the second mold part. 17. The method of claim 16, wherein the first gap is in fluid communication with at least one vacuum source, the at least one vacuum source being operable at a portion of the glass sheet opposite the first gap At least one negative pressure region is provided, a portion of the glass sheet opposite the first gap being between the first region and the second region of the glass sheet. 18. The method of claim 16, wherein the first gap is in fluid communication with at least one source of fluid such that after step (vii) fluid can be flowed through the first gap. 19. A method according to claim 1 or 2, wherein the first mold part has a mold part cover such that during step (v) the mold part cover of the first mold part is between the part and the glass plate. 20. The method of claim 19, wherein the mold part cover of the first mold part comprises a fabric. 21. The method of claim 20, wherein the fabric is a breathable fabric. 22. The method of claim 20, wherein the fabric comprises stainless steel, fiberglass, parylene terephthalamide fibers or mixtures thereof, polybenzoxazole (PBO) fibers containing graphite, and A fabric of at least one of various weaving forms of fibers. 23. A method according to claim 1 or 2, wherein the second mold part has a mold part cover such that during step (vi) the mold part covers of the second mold part between the part and the glass plate. 24. The method of claim 23, wherein the mold part cover of the second mold part comprises a fabric. 25. The method of claim 24, wherein the fabric is a breathable fabric. 26. The method of claim 24, wherein the fabric comprises stainless steel, fiberglass, parylene terephthalamide fibers or mixtures thereof, polybenzoxazole (PBO) fibers containing graphite, and A fabric of at least one of various weaving forms of fibers. 27. The method of claim 19, wherein the first mold part and the second mold part each have a respective mold part cover, and wherein the mold part cover of the first mold part and the The mold part cover of the second mold part is part of a single mold cover. 28. The method of claim 27, wherein the single mold cover comprises fabric. 29. The method of claim 28, wherein the fabric is a breathable fabric. 30. The method of claim 28 or 29, wherein the fabric comprises stainless steel, glass fibres, parylene terephthalamide fibers or mixtures thereof, polybenzoxazole (PBO) containing graphite Fibers and at least one of various weaving forms of these fibers. 31. A method according to claim 1 or 2, wherein during step (vi) the second mold part is moved relative to the first mold part by more than 2mm. 32. A method according to claim 31 , wherein during step (vi) the second mold part is moved relative to the first mold part by 4mm to 20mm. 33. A method according to claim 31 , wherein during step (vi) the second mold part is moved relative to the first mold part by 5mm to 10mm. 34. The method of claim 1 or 2, wherein the first mold part has a forming surface facing the forming support and the second mold part has a forming surface facing the forming support, And prior to step (v), the press bending device is configured such that the forming surfaces of the first mold part and the second mold part are displaced from each other by more than 2 mm. 35. A method according to claim 34, wherein prior to step (v) the press bending device is configured such that the forming surfaces of the first and second mold parts are displaced from each other by 4mm to 20mm. 36. A method according to claim 34, wherein prior to step (v) the press bending device is configured such that the forming surfaces of the first and second mold parts are displaced from each other by 5 mm to 10 mm. 37. The method of claim 1 or 2, wherein, during step (iii), the glass sheet is heated to a temperature suitable for press bending. 38. The method of claim 1 or 2, wherein, during step (iii), the glass sheet is heated to a temperature between 580°C and 700°C. 39. The method of claim 1 or 2, wherein the glass sheet is a sheet in a stack of glass sheets. 40. The method of claim 39, wherein the glass sheets are a nested pair. 41. The method of claim 1 or 2, wherein step (iv) is performed before step (iii). 42. The method of claim 1 or 2, wherein during step (iii) the glass sheet is heated on the forming support. 43. The method of claim 1 or 2, wherein after step (vii) bending is counteracted by quenching the glass sheet with a jet of cooling fluid directed against at least one major surface of the glass sheet The glass plate is thermally tempered. 44. The method of claim 43, wherein after step (vii) the curved glass sheet is laminated to another glass sheet using an interlayer structure comprising at least one sheet of interlayer material. 45. The method of claim 44, wherein the interlayer material is polyvinyl butyral, ethylene vinyl acetate copolymer, polyurethane, polycarbonate, polyvinyl chloride, or a copolymer of ethylene and methacrylic acid things. 46. The method of claim 1 or 2, wherein the first mold part is an annular ring. 47. The method of claim 1 or 2, wherein the second mold part is a monolithic mold disposed at least partially within the first mold part, and/or wherein the first mold part Two mold parts are disposed radially within said first mold part. 48. The method of claim 1 or 2, wherein the glass sheet is a soda lime silica glass composition, and/or wherein the first mold part, the second mold part and the forming support At least one of the components is equipped with a heating device. 49. The method of claim 1 or 2, wherein at least one of the first mold part and the second mold part comprises at least one of ceramic, aluminum, stainless steel, or iron. 50. The method of claim 49, wherein the iron is cast iron. 51. The method of claim 23, wherein the first mold part and the second mold part each have a respective mold part cover, and wherein the mold part cover of the first mold part and the The mold part cover of the second mold part is part of a single mold cover.

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